Optical recording medium

Abstract

Information is recorded on or reproduced from an optical recording medium ( 10 ) with irradiation of light from the opposite side of a substrate ( 2 ). In this optical recording medium ( 10 ), a reflection layer ( 6 ) is deposited on the substrate ( 2 ). This reflection layer ( 6 ) is made of an AgPdCu alloy thin layer or an AgPdCuAl alloy thin layer. A surface roughness (Ra) of this reflection layer ( 6 ) is less than 0.75 nm. A dielectric layer ( 3 ) is deposited on this reflection layer ( 6 ), and a heat control layer ( 1 ) is deposited on this dielectric layer ( 3 ). This heat control layer ( 1 ) is made of an AgPdCu alloy thin layer. A surface roughness (Ra) of this heat control layer ( 1 ) is less than 0.75 nm. A recording layer ( 4 ), a dielectric layer ( 5 ) and an organic protection layer ( 7 ) are deposited on this heat control layer ( 1 ). This optical recording medium can improve heat characteristics and reduce a disk noise.

What is claimed is:  
     
       1. An optical recording medium comprising: 
       a reflection layer deposited on at least one substrate;  
       a dielectric layer deposited on said reflection layer;  
       a heat control layer deposited on said dielectric layer; and  
       a recording layer directly deposited on and in contact with said heat control layer, wherein information is at least recorded on or reproduced from said recording layer with irradiation of light from the opposite side of said substrate, said heat control layer is made of an AgPdCu alloy thin layer, and said reflection layer comprises an AgPdCu-type alloy thin layer.  
     
     
       2. An optical recording medium according to  claim 1 , wherein said heat control layer has a surface roughness Ra less than 0.75 nm. 
     
     
       3. An optical recording medium according to  claim 1 , wherein said heat control layer has a surface roughness Ra less than 0.75 nm and said reflection layer has a surface roughness Ra less than 0.75 nm. 
     
     
       4. An optical recording medium according to  claim 1 , wherein said reflection layer is made of an AgPdCuAl alloy thin layer. 
     
     
       5. An optical recording medium according to  claim 2 , wherein said reflection layer is made of an AgPdCuAl alloy thin layer. 
     
     
       6. An optical recording medium according to  claim 3 , wherein said reflection layer is made of an AgPdCuAl alloy thin layer.